Aminopeptidase N

Aminopeptidase N (APN), also known as CD13, is an enzyme that in humans is encoded by the ANPEP gene. APN is a type II transmembrane protein and a zinc-binding enzyme that catalyzes the cleavage of amino acids from the amino terminus of protein or peptide substrates. This enzyme plays a key role in the final digestion of peptides generated from hydrolysis of proteins by gastric and pancreatic proteases. Moreover, aminopeptidase N has been identified as a crucial enzyme in the process of angiogenesis, the growth of blood vessels from pre-existing vasculature, and is also involved in various cellular processes including proliferation, migration, and survival.

Function

Aminopeptidase N is widely expressed in various tissues, including the small intestine, kidney, liver, and lungs. It is found on the surface of epithelial cells lining the intestines where it functions in the final stages of digestion of proteins to amino acids. Beyond its role in digestion, APN/CD13 is implicated in several biological processes. It is involved in the regulation of blood pressure through its role in the renin-angiotensin system, where it degrades angiotensin III to angiotensin IV. Additionally, APN has been shown to play a role in tumor cell invasion and metastasis, making it a potential target for cancer therapy.

Clinical Significance

The expression of aminopeptidase N is upregulated in various types of cancers, including leukemia, colorectal cancer, and lung cancer. Its role in tumor growth, angiogenesis, and metastasis has led to the development of inhibitors targeting APN as potential anticancer therapies. Furthermore, due to its involvement in the degradation of bioactive peptides, APN is also a target for the treatment of hypertension and other cardiovascular diseases.

Genetic

The ANPEP gene, which encodes the aminopeptidase N enzyme, is located on chromosome 15q26.2 in humans. Mutations in this gene have been associated with various diseases, although the specific conditions linked to ANPEP mutations are not well characterized.

See Also

• Enzyme
• Protease
• Angiogenesis
• Cancer
• Cardiovascular disease